Nickel anode and process for manufacturing the same



Patented Sept. 8 1925.

UNITED 'STATES NOAK VICTOR HYBINETTE, OF WILMINGTON, DELAWARE.

NICKEL ANODE AND PROCESS FOR MANUFACTURING THE SAME.

No Drawing.

To all wlzom it may concern:

Be it known that I, NOAK V1o'roR HYBI- NETTE, a citizen of the United States, residing at Wilmington, in the county of New Castle, State of Delaware, have invented certain new and useful Improvements in Nickel Anodes and Processes for Manufacturing the Same; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improved nickel anodes and to a process of producing such anodes substantially free from impurities which interfere With'the production of malleable nickel by the electrolytic method.

For certain purposes, such as the production of malleable, electrolytic nickel, it is necessary that the anode should be of extreme purity. These should particularly be no carbon, silicon or chromium, and it is desirable that the iron contents should be lower than they usually are in the'commercial nickel.

My anode consists of av casting produced by oxidizing ordinary commercial nickel in a certain way so that a solid plate can be produced therefrom which is free from lead, carbon and silicon, and can be made to contain less than 0.25 per cent and preferably less than 0.15 to 0.1 per cent of iron. I particularly desirable characteristic of the anode is its oxygen content amounting to at least one-tenth of one per cent. The presence of oxide increases the solubility of the anode in the electrolyte.

To produce the anode ordinary nickel is smelted in a reverberatory furnace and oxidized either by the addition of nickel oxide or, by oxidizing furnace ases during the smelting down period, or by blowing on it with compressed air after the metal is all smelted. By this smelting down with or without any slagging material under oxidizing conditions, I am able to remove such imprities as lead and possibly some part of the sulphur-contained in the original metal.

The next step in the process has the object of removing iron. Ordinarily one would think that silicate of nickel would enter into a reaction with oxide of iron dissolved in the metal so that silicate of iron will enter the slag and a corresponding quantity of nickel take its place in the metal. as-

Application filed June 8, 1922. Serial No. 585,753.

terial contains 1 per cent of iron and it is required to bring the iron contents down to 0.25 per cent, I find that I obtain the best results by calculating that I have to produce a slag containing the quantity of iron to be removed to the extent of 3 per cent. The slag has also at the same time to contain about four times as ymuch nickel, say 1012 per cent. The remainder of the slag has to be made up of silicates of lime, magnesia, and alumina in varying quantities. In practice I make use of ordinary gravel or sand with an addition of lime so as to make a slag consisting mainly of silicate of lime but containing enough other silicates to make a perfectly fused slag at the temperature of the furnace, say about 1550 C. It is not necessary that the sla should be particularly basic or particular y acid, and for the sake of protecting the furnace walls I prefer to have a nearly neutral slag. In round figures I add 250 pounds of a mixed silicate of lime, magnesia and alumina for 1000 pounds nickel. There is a certain improvement in the degree to which the reaction works if the slag is made to contain fluxes such as soda, borax, fiuorspar, etc., but it is'not necessary to use them. When this slag is thrown on the metal and'fused, I find that a large quantity of the oxides that were before dissolved in the metal, are ab sorbed by the slag, and that in this particular case nickel and iron enter the slag in the proportion of about four parts of nickel to one part of iron. If the preliminary oxidizing has not been sufficient, I add nickel oxide or I blow on the bath with a powerful blast of air that will penetrate the slag and oxidize the metal beneath. In this way I oxidize until the desired amount of iron has been removed from the metal. The slag is their poured off and if necessary a second slag may be put on and the procedure repeated, but for all practical purposes I find that one slagging operation is. sufficient.

lmetal to remain uncovered in the furnace for some tlme after the lIOII slag is removed,

4 but I prefer to do the smelting down without slag. It is evident that some volatile metals such as lead are more completelyi'e- -moved by such exposure of the molten metal to the furnace gases.

The metal from which now all the imp urities have been removed is preferably covered with a neutral slag so as to protect it from the furnace gases and it contains about one-half to one per cent of nickel oxide or a quantity of oxygen corresponding to that amount of nickel oxide and preferably notless than 0.1 per cent. Ordinarily oxidized nickel is supposed to be unsuitable for any practical use because when pouring it into molds it gives off gases and segregates nickel oxide so as to-produce a spongy metal of insuficient strength and of varying composition. But I find that if I regulate the oxygen contents Within the limits now mentioned, solid metal suitable for anodes is obtainedi Various changes may be made in the details of the operation as 'hereinbefore described Without departing from the invention or sacrificing any of the advantages thereof. 1 I claim:-

1. A nickel anode containing at least one-- tenth of one per cent of oxygen.

2. A nickel anode containing oxygen. 3. A cast nickel anode containing oxygen and substantially free from carbon and silicon.

4. A cast nickel anode containing oxygen free from carbon, silicon ble of dissolving metallic oxides, thereby producing purified and oxidized metal suitable to be cast into an anode.

9. A process for producing pure nickel anodes which consists in oxidizing the impurities in the nickel in the presence of a quanty of slag at least substantially equal. to ten times the Weight of the. iron to be removed from the nickel.

10. A process for producing pure nickel anodes which consists in oxidizing the impurities in the nickel in the presence of a quantity of varying from ten to thirty times the weight of the iron to be removedfrom the nickel.

11. A process of producing nickel anodes I substantially free from lead and iron, which comprises subjecting a molten bath of nickel to an oxidizing agent and continuing the oxidation in the presence of a slag capable of dissolving the iron.

12. The process of producing nickel anodes substantially free from lead andiron, which comprises subjecting a molten bath of nickel to an oxidizing agent in the presence of a slag capable of dissolving the iron, and exposing the molten metal during a period in the oxidizing operation.

In testimony whereof I aflix my signature.

NOAK VICTOR HYBINETTE. 

